ALL YOU WANT TO KNOW ABOUT…….Series.
TRIGLYCERIDES: (continued):
DIGESTION OF LIPIDS:
The human stomach partially digests the food it receives and makes it into a soup like substance known as chime. This chime is pushed into the deudonum through the phyloric-valve. The chime is acidic as the food in the stomach gets treatment from hydrochloric acid it produces. As soon as the partially digested food in the form of chime reaches deudonum the intestinal wall triggers the release of two harmones, (1) cholecystokinin (CCK) and (2) secretin. The purpose of these harmones is to stimulate secretion of pancreatic juices. It also triggers the release of bile salts from the gall-bladder which also reach the deudonum through the opening known as ampulla of vater in the pancreatic duct.
Verily, there are a number of enzymes available in the pancreatic juice. In so far as fats and oils i.e, lipids are concerned only lipase is important.. First, the bile salts emulsify the lipids into tiny droplets and second enzyme lipase breaks them down into droplets of fatty acid and monoglycerides. It happens that the enzymes sometime free two ends of a triglyceride of fatty acids leaving the middle fatty acid attsached. This is referred to as monoglyceride.
(Triglycerides and monoglyceriders. )
Fatty acids and monoglycerides go through the epithelial cells of the villi of the ileum, the 12 feet long intestinal portion which follows the 8 feet intestinal portion known as jejunum where they are again converted back into triglycerides. ( For your information, small intestine has three parts viz., deudonum, jejunum and ileum. ) After this, they are passed on to the lymphic system. Now, the triglycerides in the lymphic system are carried away from the ileum and delivered to the blood stream.
You are aware that lipids are soluble only in fats as they are fat soluble. In other words, they cannot be solved in water. But your blood stream and the lymphatic system both are mainly comprised of water. However, short-chain fatty-acids are considered to be water soluble to some extent and they are absorbed by the cells of the intestinal wall.
The long-chain fatty acids are connected again to monoglycerides or to glycerol to create new triglycerides To move about, they require lipoproteins. We will discuss all about lipoproteins in the next article. .